I don't know if both Clockports will work at the same time, I hope they do because the 4-Port Clockport Expander doesn't work on the A603 unfortunately.
I don't have one of AmigaKit's Clockport adapters, but here's a photo of my A600 with an A603, Subway, Kickstart ROM Switcher and IDE-CF adapter installed inside, it might give you a bit of an idea of how much space is left with that stuff at least:
